alga

In a sentence

• Les algues marines són un aliment nutritiu.

  Seaweeds are a nutritious food.

  Here, 'algues' is the plural form of 'alga' used as a noun to denote seaweeds.

• L'alga es mou amb el corrent de l'aigua.

  The seaweed moves with the water current.

  In this sentence, 'alga' is singular and used as a noun referring to a specific seaweed.

• Estem estudiant la biologia de l'alga.

  We are studying the biology of the seaweed.

  The word 'alga' here is singular and used to refer to seaweed in a scientific context.